Stretching instrument



FIG. 1 is a front elevational view of the stretching instrument, showing my new design;

FIG. 2 is a rear elevational view thereof;

FIG. 3 is a right-side elevational view thereof;

FIG. 4 is a left-side elevational view thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is a bottom plan view thereof;

FIG. 7 is a top perspective view thereof; and,

FIG. 8 is a bottom perspective view thereof.

The evenly spaced broken lines depict unclaimed parts of the stretching instrument and form no part of the claimed design. 

CLAIM The ornamental design for a stretching instrument, as shown and described. 